Fix async-std by special-casing rustdoc in typeck

src/librustc_privacy/lib.rs

@@ -779,11 +779,18 @@ impl Visitor<'tcx> for EmbargoVisitor<'tcx> {
  // The interface is empty.
  hir::ItemKind::GlobalAsm(..) => {}
  hir::ItemKind::OpaqueTy(..) => {
- // FIXME: This is some serious pessimization intended to workaround deficiencies
- // in the reachability pass (`middle/reachable.rs`). Types are marked as link-time
- // reachable if they are returned via `impl Trait`, even from private functions.
- let exist_level = cmp::max(item_level, Some(AccessLevel::ReachableFromImplTrait));
- self.reach(item.hir_id, exist_level).generics().predicates().ty();
+ // HACK(jynelson): trying to infer the type of `impl trait` breaks `async-std` (and `pub async fn` in general)
+ // Since rustdoc never need to do codegen and doesn't care about link-time reachability,
+ // mark this as unreachable.
+ // See https://github.com/rust-lang/rust/issues/75100
+ if !self.tcx.sess.opts.actually_rustdoc {
+ // FIXME: This is some serious pessimization intended to workaround deficiencies
+ // in the reachability pass (`middle/reachable.rs`). Types are marked as link-time
+ // reachable if they are returned via `impl Trait`, even from private functions.
+ let exist_level =
+ cmp::max(item_level, Some(AccessLevel::ReachableFromImplTrait));
+ self.reach(item.hir_id, exist_level).generics().predicates().ty();
+ }
  }
  // Visit everything.
  hir::ItemKind::Const(..)

src/librustc_typeck/check/mod.rs

@@ -1967,10 +1967,16 @@ pub fn check_item_type<'tcx>(tcx: TyCtxt<'tcx>, it: &'tcx hir::Item<'tcx>) {
  check_union(tcx, it.hir_id, it.span);
  }
  hir::ItemKind::OpaqueTy(hir::OpaqueTy { origin, .. }) => {
- let def_id = tcx.hir().local_def_id(it.hir_id);
-
- let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
- check_opaque(tcx, def_id, substs, it.span, &origin);
+ // HACK(jynelson): trying to infer the type of `impl trait` breaks documenting
+ // `async-std` (and `pub async fn` in general).
+ // Since rustdoc doesn't care about the concrete type behind `impl Trait`, just don't look at it!
+ // See https://github.com/rust-lang/rust/issues/75100
+ if !tcx.sess.opts.actually_rustdoc {
+ let def_id = tcx.hir().local_def_id(it.hir_id);
+
+ let substs = InternalSubsts::identity_for_item(tcx, def_id.to_def_id());
+ check_opaque(tcx, def_id, substs, it.span, &origin);
+ }
  }
  hir::ItemKind::TyAlias(..) => {
  let def_id = tcx.hir().local_def_id(it.hir_id);

src/librustc_typeck/lib.rs

@@ -356,6 +356,7 @@ pub fn check_crate(tcx: TyCtxt<'_>) -> Result<(), ErrorReported> {
  tcx.sess.time("wf_checking", || check::check_wf_new(tcx));
  })?;
 
+ // NOTE: This is copy/pasted in librustdoc/core.rs and should be kept in sync.
  tcx.sess.time("item_types_checking", || {
  for &module in tcx.hir().krate().modules.keys() {
  tcx.ensure().check_mod_item_types(tcx.hir().local_def_id(module));

src/librustdoc/core.rs

@@ -452,10 +452,20 @@ pub fn run_core(options: RustdocOptions) -> (clean::Crate, RenderInfo, RenderOpt
  // Certain queries assume that some checks were run elsewhere
  // (see https://github.com/rust-lang/rust/pull/73566#issuecomment-656954425),
  // so type-check everything other than function bodies in this crate before running lints.
+
  // NOTE: this does not call `tcx.analysis()` so that we won't
  // typeck function bodies or run the default rustc lints.
  // (see `override_queries` in the `config`)
- let _ = rustc_typeck::check_crate(tcx);
+
+ // HACK(jynelson) this calls an _extremely_ limited subset of `typeck`
+ // and might break if queries change their assumptions in the future.
+
+ // NOTE: This is copy/pasted from typeck/lib.rs and should be kept in sync with those changes.
+ tcx.sess.time("item_types_checking", || {
+ for &module in tcx.hir().krate().modules.keys() {
+ tcx.ensure().check_mod_item_types(tcx.hir().local_def_id(module));
+ }
+ });
  tcx.sess.abort_if_errors();
  sess.time("missing_docs", || {
  rustc_lint::check_crate(tcx, rustc_lint::builtin::MissingDoc::new);

src/test/rustdoc-ui/error-in-impl-trait/async.rs

@@ -1,10 +1,7 @@
 // edition:2018
+// check-pass
 
-/// This used to work with ResolveBodyWithLoop.
-/// However now that we ignore type checking instead of modifying the function body,
-/// the return type is seen as `impl Future<Output = u32>`, not a `u32`.
-/// So it no longer allows errors in the function body.
+/// Should compile fine
 pub async fn a() -> u32 {
  error::_in::async_fn()
- //~^ ERROR failed to resolve
 }

src/test/rustdoc-ui/error-in-impl-trait/closure.rs

@@ -1,5 +1,5 @@
+// check-pass
 // manually desugared version of an `async fn` (but with a closure instead of a generator)
 pub fn a() -> impl Fn() -> u32 {
  || content::doesnt::matter()
- //~^ ERROR failed to resolve
 }

src/test/rustdoc-ui/error-in-impl-trait/generic-argument.rs

@@ -1,7 +1,7 @@
+// check-pass
 trait ValidTrait {}
 
 /// This has docs
 pub fn f() -> impl ValidTrait {
  Vec::<DoesNotExist>::new()
- //~^ ERROR failed to resolve
 }

src/test/rustdoc-ui/error-in-impl-trait/impl-keyword-closure.rs

@@ -1,6 +1,6 @@
+// check-pass
 pub trait ValidTrait {}
 /// This returns impl trait
 pub fn g() -> impl ValidTrait {
  (|| error::_in::impl_trait::alias::nested::closure())()
- //~^ ERROR failed to resolve
 }

src/test/rustdoc-ui/error-in-impl-trait/impl-keyword.rs

@@ -1,6 +1,6 @@
+// check-pass
 pub trait ValidTrait {}
 /// This returns impl trait
 pub fn g() -> impl ValidTrait {
  error::_in::impl_trait()
- //~^ ERROR failed to resolve
 }

src/test/rustdoc-ui/error-in-impl-trait/realistic-async.rs

@@ -0,0 +1,28 @@
+// edition:2018
+// check-pass
+
+mod windows {
+ pub trait WinFoo {
+ fn foo(&self) {}
+ }
+
+ impl WinFoo for () {}
+}
+
+#[cfg(any(windows, doc))]
+use windows::*;
+
+mod unix {
+ pub trait UnixFoo {
+ fn foo(&self) {}
+ }
+
+ impl UnixFoo for () {}
+}
+
+#[cfg(any(unix, doc))]
+use unix::*;
+
+async fn bar() {
+ ().foo()
+}

src/test/rustdoc-ui/error-in-impl-trait/trait-alias-closure.rs

@@ -1,3 +1,4 @@
+// check-pass
 #![feature(type_alias_impl_trait)]
 
 pub trait ValidTrait {}
@@ -6,5 +7,4 @@ type ImplTrait = impl ValidTrait;
 /// This returns impl trait, but using a type alias
 pub fn h() -> ImplTrait {
  (|| error::_in::impl_trait::alias::nested::closure())()
- //~^ ERROR failed to resolve
 }

src/test/rustdoc-ui/error-in-impl-trait/trait-alias.rs

@@ -1,3 +1,4 @@
+// check-pass
 #![feature(type_alias_impl_trait)]
 
 pub trait ValidTrait {}
@@ -6,5 +7,4 @@ type ImplTrait = impl ValidTrait;
 /// This returns impl trait, but using a type alias
 pub fn h() -> ImplTrait {
  error::_in::impl_trait::alias()
- //~^ ERROR failed to resolve
 }

src/test/rustdoc-ui/infinite-recursive-type-impl-trait-return.rs

@@ -0,0 +1,15 @@
+// normalize-stderr-test: "`.*`" -> "`DEF_ID`"
+// normalize-stdout-test: "`.*`" -> "`DEF_ID`"
+// edition:2018
+
+pub async fn f() -> impl std::fmt::Debug {
+ #[derive(Debug)]
+ enum E {
+ //~^ ERROR recursive type `f::{{closure}}#0::E` has infinite size
+ This(E),
+ Unit,
+ }
+ E::Unit
+}
+
+fn main() {}

src/test/rustdoc-ui/infinite-recursive-type-impl-trait-return.stderr

@@ -0,0 +1,17 @@
+error[E0072]: recursive type `DEF_ID` has infinite size
+ --> $DIR/infinite-recursive-type-impl-trait-return.rs:7:5
+ |
+LL | enum E {
+ | ^^^^^^ recursive type has infinite size
+LL |
+LL | This(E),
+ | - recursive without indirection
+ |
+help: insert some indirection (e.g., a `DEF_ID` representable
+ |
+LL | This(Box<E>),
+ | ^^^^ ^
+
+error: aborting due to previous error
+
+For more information about this error, try `DEF_ID`.

src/test/rustdoc-ui/infinite-recursive-type-impl-trait.rs

@@ -0,0 +1,7 @@
+fn f() -> impl Sized {
+ enum E {
+ //~^ ERROR recursive type `f::E` has infinite size
+ V(E),
+ }
+ unimplemented!()
+}

src/test/rustdoc-ui/infinite-recursive-type-impl-trait.stderr

@@ -0,0 +1,17 @@
+error[E0072]: recursive type `f::E` has infinite size
+ --> $DIR/infinite-recursive-type-impl-trait.rs:2:5
+ |
+LL | enum E {
+ | ^^^^^^ recursive type has infinite size
+LL |
+LL | V(E),
+ | - recursive without indirection
+ |
+help: insert some indirection (e.g., a `Box`, `Rc`, or `&`) to make `f::E` representable
+ |
+LL | V(Box<E>),
+ | ^^^^ ^
+
+error: aborting due to previous error
+
+For more information about this error, try `rustc --explain E0072`.